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Need help with a schematic

TheAverage

Feb 21, 2014
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Feb 21, 2014
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Hi Guys,

I'm from Belgium and in my spare-time i like to work on electronics. I began with this hobby not too long ago, so I don't really know a lot about it. But I've got this project on my mind that I really want to work on, so here it goes.

I'm going to make a scoreboard. I'm going to use the 74LS47 as decoder for 2 of my 5" inch LED displays. Everything should be used at 9V. But here's the thing. I want to be able to count up and down from a distance, like with a remote control. How would I be able to do that and which IC should I use for that. And also if I use 9V for the displays, it's a too big voltage for my IC. What should I do?

If anyone could just show me a schematic, I could even start today!

I really don't know a lot on the subject, since I started this hobby with my cousin not too long ago. Any help at all would be greatly appreciated.

Thank you guys


LINKS TO COMPONENTS:
http://www.futurlec.com/74LS/74LS47.shtml
http://www.futurlec.com/LED/7SR50011BS.shtml
 

Harald Kapp

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Nov 17, 2011
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Welcome aboard this forum.

You can use e.g. a 74HC192 up-down counter IC, one for each digit to count.
You can use a 74HCT4511 BCD-to-7-segment decoder to drive the 7-segment display. Note that you will need an inverting driver stage (figure 13 in the datasheet) to drive the common anode display you want to use.
You can use a 7805 regulator to create 5V from 9V.

If you plan to use a 9V battery: have you considered the lifetime of the battery with respect to the current consumptionj of the LEDs in the display?

The display you linked to has a typical forward voltage of 9.25V (11V max.). Considering voltage drop across the driver output and some current limiting resistor (read here) you should opt for at least 10V to supply the display.
 
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